John Leslie

Forse il filosofo più perspicace nel difendere l’ idea di un Progetto Intelligente:

The philosopher who has occupied himself most extensively with the Anthropic Principle is John Leslie, to whom Swinburne alludes. Though self-confessedly neither a Christian nor even a traditional theist, Leslie has argued repeatedly that the observed delicate balance of conditions requisite for the existence of intelligent life at this point in cosmic history does require an explanation and that the explanation of intelligent design is superior to any alternative. He argues against those who would short-circuit the demand for an explanation by objecting that since the universe is unique, the probability of its present complexity cannot be assessed, or that though the balance of conditions in the universe is improbable, still any improbable condition will obtain once and that "once" could be the first time.20 According to Leslie, without the Many-Worlds cosmology, the claim that no explanation of the universe's order is needed is "ludicrous"; it is like a person emerging unscathed after being machine-gunned from fifty yards for fifty minutes and who shrugs off the need for any explanation of his being alive by saying that all the bullets' missing, though improbable, could happen and that he wouldn't be there to ask about it unless that possibility were realized.21 According to Leslie, the standard objections to the design argument threaten to delay the development of science, for if these objections were correct, there would be no reason for developing Many-Worlds cosmologies, which are important to science. He notes that there is no independent evidence for the existence of many worlds except for the existence of intelligent life itself and that the attraction of the Many-Worlds scenario for many scientists shows that they recognize that the fine-tuning apparently present in the universe does cry out for explanation. But the evidence for a Many- Worlds model is equally evidence for an intelligent designer. Both hypotheses are rendered more probable by the observed features of the universe than they would be in the absence of such features. This conclusion alone, it seems to me, is highly significant, for it confronts us with a dilemma, both horns of which involve heavy metaphysical commitments. Are we going to posit God or a World Ensemble? According to Leslie, this is the choice that we must make if we do not choose simply to ignore the problem. He points out that most of the Many-Worlds theories are obscure and incomplete and that the God- hypothesis is neither unscientific nor more obscure than those theories. Moreover, individual models for generating the World Ensemble can be criticized… Despite such problems, people continue to believe in Many-Worlds scenarios, opines Leslie, because they feel that without them there is no explanation of how intelligent life did originate…

In che modo il “multiverso” ci parla di Dio

Non avete pagato il pizzo e i sicari della mafia intendono darvi una lezione; una volta scoperti tentate la fuga infilandovi in un vicolo cieco ma vi hanno visto e vi inseguono, siete ormai con le spalle al muro, sono in cinque e da pochi passi scaricano le loro mitragliette su di voi.

Dopo la raffica infinita vi accorgete di essere illesi, tutte le pallottole vi hanno solo sfiorato.

A questo punto potete 1) o tentare di spiegarvi in qualche maniera quanto accaduto o 2) liquidare la faccenda come una casualità: vi hanno semplicemente mancato.

Quale vi sembra l’ atteggiamento più sensato?

Quella appena descritta è una buona analogia dell’ Uomo nell’ Universo, lo sostiene il filosofo John Leslie: l’ estrema improbabilità di questo universo e della nostra esistenza puo’ essere spiegata o accettata come casuale.

Dall’ analogia traspare in modo evidente quale sia l’ atteggiamento più ragionevole. Come potremmo infatti mai pensare ad una casualità?

D’ altronde il concetto di “multiverso” testimonia che anche gli scienziati duri e puri tentano di darsi una spiegazione. Gli universi paralleli, infatti, non sono osservabili per definizione, la scienza dovrebbe disinteressarsene, eppure la loro esistenza è postulata al fine di togliere casualità alla origine dell’ universo in cui viviamo.

A questo punto Leslie si chiede: ma la spiegazione teista non è forse più semplice di quella cervellotica degli infiniti universi paralleli?